Nationwide Retrospective Analysis of Early Complications after Adult Spinal Deformity Surgery

Study Design. Retrospective nationwide registry-based observational study. Objective. To determine the incidence of and factors associated with early complications following surgery for adult spinal deformity (ASD). Summary of Background Data. Complications after ASD surgery contribute to morbidity, mortality, and health care costs. Prior studies were limited by small sample sizes and incomplete surgical information. The Japanese Spinal Instrumentation Society database (JSIS-DB) includes detailed instrumentation data, enabling a robust secondary analysis of perioperative factors. Methods. We analyzed JSIS-DB data from patients undergoing ASD surgery involving the fusion of three or more vertebrae between 2018 and 2022. Demographics, comorbidities, and surgical variables (fusion length, osteotomy, interbody fusion type, minimally invasive surgery MIS, staged procedures, navigation, and neuromonitoring) were assessed. The primary endpoint was ultra-early perioperative complications within 2 weeks, classified as major (mortality, massive bleeding, neurological, cardiopulmonary, or infectious events) or minor (dural injury, delirium, or urinary tract infection). Multivariable logistic regression was used to identify the associated factors. Results. Among 3,193 patients (mean age 60.8 years), the overall complication rate was 28.5%, including 25.4% with major complications and 0.1% with mortality. Increased risk was associated with operative time >5 h (adjusted odds ratio aOR 4.40; 95% CI 3.60–5.47), fusion >5 levels (aOR, 1.51; 95% CI 1.20–1.91), posterior/transforaminal interbody fusion (PLIF/TLIF) (aOR, 1.47; 95% CI, 1.20–1.79), and three-column osteotomy (3CO) (aOR 3.50; 95% CI 2.21–5.53). Reduced risk was associated with adult idiopathic scoliosis (aOR, 0.48; 95% CI, 0.37–0.63), staged surgery (aOR, 0.24; 95% CI, 0.18–0.32), lateral lumbar interbody fusion (LLIF) (aOR, 0.74; 95% CI 0.58–0.95), and MIS (aOR, 0.65; 95% CI 0.49–0.86). Respiratory complications, massive bleeding, neurological deficits, surgical site infections, and proximal junctional kyphosis were associated with prolonged hospitalization (>30 days). Conclusions. This nationwide registry analysis demonstrated that prolonged operative time, long fusion, PLIF/TLIF, and 3CO increase the early complication risk after ASD surgery, whereas staged surgery, LLIF, and MIS are protective. Level of Evidence. Level III (retrospective cohort study)